Main: Copy Paste range selection no longer replaces old dynamics

Issue type

UX/Interaction bug (incorrect behaviour)

Description with steps to reproduce

1. Make a range selection with dynamics
2. Copy paste onto another staff with dynamics
3. In 4.7, old dynamics are replaced with new ones
4. In main, old dynamics remain and can collide with new ones

Supporting files, videos and screenshots

https://github.com/user-attachments/assets/f7954173-78d6-4fdd-8852-27ec49a39fcb

In which versions of MuseScore Studio is this issue present?

OS: macOS Tahoe (26.6.2), Arch.: arm64, MuseScore Studio version (64-bit): 5.0.0-260917031, revision: github-musescore-musescore-9196e73

Regression

Yes, this works in the latest released version and is broken in the nightly builds

Operating system

MacOS Tahoe 26.2,

Additional context

No response

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible